<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta http-equiv="X-UA-Compatible" content="IE=edge">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <title>Document</title>
</head>
<body>
  <h1 onclick="alert(123)" onmouseover="alert('来了 老弟')">早点脱单吧，我怕你孤独终老，却又长命百岁</h1>

  <script>
    // h1.onclick = function(){}

    // h1.addEventListener('click', function(){}, )
  </script>
</body>
</html>